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Smokers and Drinkers Are Epigenetically Older

A team of researchers lead by scientists from the University of Iowa have discovered that smoking and drinking accelerates the epigenetic changes associated with aging. The study, presented at the American Society of Human Genetics (ASHG) 2015 Annual Meeting, shows that the DNA methylation patterns of smokers and drinkers are coincident with those of aging. Calculating the difference between the biological and chronological age of the studied subjects, they could quantify the influence of smoking and drinking in aging.

Biological aging depends partially in lyfestyle. Smoking and drinking are quite extended behaviours in society, and are known to alter the health of consumers, even to the point of causing death. Previous works demonstrate that DNA methylation patterns change with aging and also depend on lyfestyle choices like the ones mentioned above. This has consequences in cellular physiology, given that methylation causes genes to change its expression levels.

Dr. Philibert and coworkers decided to use epigenetic data from 800 people retrieved from the Gene Expression Omnibus -a genomics data repository- to better understand the relationship between biological aging and the consumption of those substances. Genome methylation was assessed with the Illumina HumanMethylation 450k BeadChip, allowing to determine the biological age of each individual according to a previously determined epigenetic clock based on the methylation level of 71 specific sites. Next, they assessed the substance consumption by quantifying the methylation levels in two genomic sites in chromosome 10, already known to be affected by smoking and drinking (this approach is more reliable than self-reported use of substances). With all this data, the researchers could calculate the difference between the biological and the chronological age for each person and the substance use levels, and thus the influence of smoking and drinking in aging.

Smoking is always bad, drinking a bit is good

The researchers discovered that any level of smoking accelerates epigenetic/biological aging. On the other hand, a moderate alcohol consumption -one or two drinks per day-  is linked to healthy aging, whereas low or high consumption cause premature aging.

This method will be very useful to quantify the effect of substance use and address problems objectively. The researchers are currently working to understand how these epigenetic changes happen in response to smoke and alcohol.

Source: ASHG